Today's EGR engines are putting as much as 30% of the exhaust gas back into the engine. Engines built between 2002 and 2007 were adding 15% or more exhaust gas into the engine. Crankcase ventilation systems have been closed, increasing the potential for trapping exhaust by-products which can and do get into the oil. One of the primary modes of valve-train wear is associated with soot particles in the engine. It is critical to have strong dispersant characteristics in the oil to keep the soot particles from agglomerating. It is essential to the health of the engine that these particles remain small and suspended in the oil. [END QUOTE]
Now to the differences between mineral based oils and Synthetics:
ALL oils start with a "Base Oil", which is about 85-90 percent of the finished product, and rest of the finished product is additives.
There are currently three different classes of "Base stocks" to make engine oil from. Mineral based, Highly Refined Mineral oil, and the synthetic based oils.
Mineral oils are formed through decomposition of a variety of organic matter such as fish, sea weed, trees, birds, grass, dinosaurs, etc.
Highly Refined Mineral Oils are just that. They are more refined which involves a variety of separation, hence a better Base oil to start from, but more costly to produce than petroleum.
Synthetic Base stocks in contrast to petroleum are built up from one or more specific organic compounds. They are well defined and are comprised of particular molecule types that have been designed for specific performance characteristics. One distinct advantage of synthetics is that they can be "tailor made" to fit the requirements of the application.
There are currently 4 suitable synthetic base lubricants; Polyalphaolefin (PAO's), Synthetic Esters which include Dibasic Acid Esters (Diesters), Polyol Esters, and Polyalkylene Glycols (PAGs). The most common is the (PAO) Polyalphaolefin.
Of course each has their advantages and disadvantages. This is why the Amsoil Company uses a combination of "Synthetic Base stocks" to get the very best there is to offer. It is more costly, but in the long run, it becomes less expensive, as the oil provides excellent lubricity, improved energy efficiency, high viscosity index, low pour points(as low as -72 F. ) excellent thermal and oxidative stability, high flash and fire points, and is fire resistance. And will last longer in use. (Longer oil drain intervals)
Group I base oils can have a mix of different hydrocarbon chains, with relatively little uniformity; these oils are the least refined. They are usually not used for autos.
Group II is the most common base oils in “dino juice,” with good performance in most areas except cold temperature viscosity.
Group III is called synthetic, and has high molecular uniformity and stability. Group III oil bases are used in most synthetic oils.
Group IV is chemically engineered stocks, arguably with the highest performance and longevity.
Wayne
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